When it comes to Sen. John Cornyn’s amendment to the immigration bill, Rep. Joaquin Castro said today he doubts it will help the reform cause and considers it to be a “poison pill.”

When asked about the San Antonio Republican senator’s amendment in an interview on MSNBC, the San Antonio Democratic congressman said, “It’s more of his attempt to secure his reelection in Texas in 2014.”

Castro theorized that Cornyn fears a right-wing challenge in the 2014 GOP Senate primary so is sounding tough on immigration.

“I’m hoping enough Republicans will see past that,” Castro said.

Arizona Sen. Jeff Flake, a GOP member of the immigration Gang of Eight, defended Sen. John Cornyn in an interview with Dallas News and said, “I don’t think it’s a poison pill. He has said publicly, he said again in our lunch meeting yesterday, `if my amendment is adopted I will vote for the bill.’ He has said that on a number of occasions and I believe him.”

According to Castro, a lot of the rhetoric being used in the debate makes Hispanic Americans feel like they aren’t accepted as part of the American family. Castro believes that if enough Republicans join with the Democratic majority to pass the bill overwhelmingly in the Senate, immigration reform could gain significant momentum.

Some democrats say Cornyn’s amendment would be impossible to implement and would cause the carefully balanced bill to fall apart. The amendment would require 100 percent situational awareness and an increase in physical border security.

However, according to an article on Yahoo! News, Democratic Gang of Eight member, Sen. Michael Bennett, said he would be open to adding a requirement for a 90 percent apprehension rate of individuals who illegally cross the border because the bill’s focus on increased border security, its mandatory workplace verification, and its guest worker programs would stem the flow of illegal immigrants.

Castro said that Cornyn’s amendment follows an “old tradition style of boots on the ground border enforcement and it’s really a shame that it doesn’t deal more with the future and technology,” he said.

The San Antonio Democrat said that the 82-15 vote to move forward with the immigration bill was very promising, but added that Republicans are sending conflicting signals about where the party will go.